USDOT STUDY:Truck Size & Weight Review Calls for Big Rigs

USDOT’s “Comprehensive Truck Size and Weight Study” Vol III Scenario Analysis (TS&W) suggests enormous benefits to users from allowing longer and heavier truck combinations on a nationwide network, and from harmonizing truck standards with neighbors north and south. The faint-hearts who put out this study do not directly compare the benefits and the costs. They apparently don’t want to make the net benefits of such road trains too obvious because this is a controversial matter. Apparently someone in the Clinton Admin has said: “We don’t like big trucks.” There!

But even a cursory examination of the TS&W data shows potential benefits from big rigs that dwarf the costs.

Of course rail interests and enthusiasts object strenuously to competition from more efficient truck combinations than are presently run on US highways. And larger longer trucks are often a hot button political issue for some of the American public, provoking passionate assertions (based on anecdote, and gut feeling) that they pose a terrible safety hazard to car drivers. This TS&W study is agnostic on the safety issue, saying the evidence is mixed and experience with long combination vehicles (LCVs) is insufficient to make a judgment. True in the US, but this is not the whole world, guys. Experience in Australia and Canada suggests that moving heavy truck traffic into fewer, better engineered road trains confined to designated heavy truck routes, is a major safety advance.

Environmental benefits from larger truck combos however are quite clearcut in the USDOT analysis. The long truck combos greatly reduce vehicle-miles traveled, fuel consumption, and emissions – and this is after allowing for the extra traffic picked up from rail. The USDOT study does have the courage to start to challenge the USEPA by stating forthrightly that there are major fuel conservation benefits (6.2% for tridems, 13.8% for LCVs, 12.8% for triples) and probably corresponding reductions in exhaust emissions, and major clean air benefits.

“The estimated reduction of 8b mi in heavy commercial truck travel on urban roads (from allowing triples on the postulated national network) indicates that air pollution costs would be reduced in those areas prone to significant air pollution.” (p10-12) A 5b veh-mi reduction in urban truck travel is modeled for LCVs, and for going to heavier tri-axle trailers.

BIG BIG user benefits

The big news is that potential shipper cost savings range between $13b/yr and $29b/yr in several different scenarios analyzed in the study. Given that total shipper costs in the whole US economy are currently around $250b/yr these numbers suggest major potential savings for the nation, and an improved standard of living and greater competitiveness from the more efficient truck system. Presently less than a billion of the 128b (0.7%) veh mi-traveled in the US by trucks are in triples and long doubles, these being only allowed in the Rocky Mtns, the plains states and on several turnpikes (IN, OH, FL, NY). IL and PA are major obstacles to heavy trucking to the northeast, and apart from intra-FL movement there is no regular heavy trucking in the southern states at all, and none in key coastal states such as CA, VA, MD, NJ, CT and MA. By contrast to the US’s 0.7%, in Canada 18.5% of the fleet and probably a third of the veh-mi of trucking consist of these efficient LCVs. In Mexico the numbers are about 4% and 10%.

The US is also backward in not exploiting the advantages of a triple axle semi-trailer (‘tridem’) which spares the pavement and allows heavier weights in a regular truck-trailer combination for the same or less pavement damage. These tri-axle trailers constitute only 5% of the US fleet compared to 25% in Canada and 50% in Mexico. Reason is the US regulations have no specific provision for a tridem so the 80kpd overall combination limit means that payload is reduced by the weight of the third trailer axle. Regular 40' containers loaded within international ISO weight limits (30.5t) are overweight on most US roads without special permits and paperwork, again because of the 80kpd overall weight limit in all the seaboard states. The 80kpd (36.3t) weight limit common in the US for a semi-trailer (truck plus cargo) compares with European 97kpd (44t), Canada 103kpd (46.5t) and Mexico 107kpd (48.5t).

It’s da bridges wot need da work

Implications of the heavier weights and longer combos for pavement upkeep are quite small, the study reveals. The tridem and LCV-nationwide proposals actually reduce pavement maintenance though the amount is insignificant, while the 7-axle triples increases it, also very slightly. Roadway geometry modifications to ramps to allow for the extra off-tracking of the long trailers are $3.8b one-off for the LCVs-nationwide, but insignificant or zero for the others. Major expense there would be about 2600 staging areas on the network for the road trains to be made up and broken down at the transitions between the heavy trucking network and the local roads - $1.7b capital cost. LCVs nationwide would cost $3.8b capital cost over the baseline, the tridems only $100m and triples nothing.

Bridges are the really big cost for the road-trains, the study suggests. Pavement just spreads the extra loads over extra axles and extra tires and in most cases there is little net impact on maintenance costs. Bridges are another matter. Short bridges are more affected by short trucks of a given load, but basically it is gross weight that busts them. A major bridge rebuild program ranging from $16b for the triples to $65b for the 51kpd tridems would be needed, according to the USDOT.

The study has some incredible user delay numbers for the various bridge rebuild scenarios, ranging between $101b for the strengthening of bridges to triples, to $266b for strengthening for long doubles. Most estimates of nationwide congestion on all US roads from all sources – incidents, undercapacity, and construction work – are in the range $50b to $100b/yr, so these numbers look suspiciously high. Congestion delays during rebuilding of bridges are put by USDOT at 4 to 6 times the cost of actual rebuild itself!

Near-standard procedures for rebuilding in congested conditions now include confining lane-reducing work to the small hours of the morning, using prefab deck components for quick reopening, constructing an extra lane alongside before closing an existing lane, making use of shoulder and narrowing lanes, using temporary bridging etc. None of this is taken into account in the USDOT study. Heck, that $266b is about the Pentagon budget. These are totally absurd numbers because no bridge rebuild managers could get away with imposing such congestion costs. In any real world rebuild program bridge reconstruction would be conducted with contract provisions for maintaining capacity, and incentives to maintain traffic flow. I am assuming user delay costs will be equivalent to capital costs, rather than 4 to 6 times them, as USDOT says.

Triples no-brainer

The no-brainer on this analysis is to allow triples on a nationwide network. For a one-time capital cost, mostly on strengthening bridges of $16b, and another equivalent user delay cost, there is an annual benefit to users hereafter of $22b – from lower freight rates. That’s a 70% annual return on investment and even with the study’s grossly inflated user delay costs of $101b it is a 19% return.

LCVs nationwide produce the largest gain in annual user benefits - $29b/yr. The costs include nearly $4b in capital works on road geometry upgrades, and $53b of bridge rebuilding. If we assume equivalent user costs during rebuild that is an investment of $110b, and a return of 26%, also a terrific national investment. If you put in the Pentagon-budget sized USDOT $-number for delays during reconstruction, $266b, then total investment required is $323b, or 9%pa, still a respectable return.

The tridem scenarios would be part of a harmonization of US truck standards with those of Mexico and Canada. The 44kpd (20t) tri-axle offers user-benefits also $13b with similar bridge reconstruction costs to the LCVs scheme ($51b vs $53b) but the heavier tri-axle trailer arrangement of 51kpd (25t) involves the most extensive bridge rebuild work – $65b. Throw in the same user delays during rebuild and the total upfront cost is $130b. For that there are annual user benefits of $17b, or a 13% return annually.

Clearly the key to making this pay is reducing disruption during bridge rebuild. The capital costs are small relative to the payoffs.

The study is very negative in its portrayal of the impact of longer truck combos on rail. It projects losses of 5% to 9% of carload-mi to the long trucks. It assumes rail is powerless to resist the increased competitiveness of trucking, neglecting the possibility of the railroads improving their productivity as well. The conclusions of the rail competition chapter sound as if they were penned directly by the American Railroads Assoc lobbyists: “...no industry can endure the loss...” , “the effects would be predictable: total elimination of any shareholder distributions and cancellation of capital spending at a minimum”etc. Tough luck if this is simply the result of two technologies competing on their merits and one being unable to hack it on fundamental cost. If rail cannot compete with pavement let us keep a few museum pieces for visitors to take Sunday rides in remembrance of a great 19th century technology.

Poor pricing

But in truth the present system of highway user charges doesn’t price heavy trucks properly. It prices the light ones too much and the heavy ones too little (see p1-6), and provides no incentive to truckers to deploy extra axles to reduce pavement damage, as shown in the USDOT’s Highway Cost Allocation Study (see TRnl#26 Apr98 p13). The present arrangements of state-owned highways and politically determined road charges by state and federal governments make nearly impossible any rational economic collaboration between roadway managers and designers, on one side, and important roadway users like the truckers over the best combination of size and weight arrangements and charges for each.

The study notes this in a roundabout way, acknowledging that current highway construction practices are assumed unchanged (p2-4) adding: “We know however that pavements can be built to accommodate heavier axle loadings as is done in Europe. A full life-cycle cost analysis would include significant tradeoffs of initial cost requirements and, recurring public and private costs, and the extent of the system that could be brought up to a higher standard.” Ken Small, Winston & Evans in “Road Work” (Brookings 1989) tackled this issue and concluded that the present free highways in the US are generally underbuilt for minimum life-cycle cost. Optimal pavements would be 2" to 3" thicker, they found (p42).

This is where the turnpikes, to the extent they are free of political control, have an opportunity to strike out on their own. A couple have – Indiana and Ohio and the NY State Thruway garner huge revenues from making special efforts to cater to long efficient truck combos. NJ and PA however don’t.

Maybe the turnpikes and the truckers could usefully get together to sponsor more research on this? Or it could be part of the value pricing program’s study of truck lanes in Los Angeles and elsewhere? If new truck lanes are put out to bid, potential investors and lenders will want more ideas on how to build roads for efficient truck combos.

Forgot truck lanes

One thing the TS&W study did not examine at all was the potential for segregating traffic. What real need is there to rebuild all lanes of bridging on a 45k mi or 65k mi network of roads at costs of $16b to $65b, and incur mind-boggling delay costs, when it might be possible to confine the heavies to their own lanes with only those lanes being rebuilt (or built anew) to the higher weight (and size) standards? The case for heavy truck lanes has not even been addressed by the Feds yet. What pathetically limited imagination do we have at USDOT? It has been left to the locals in Los Angeles (SCAG) to take the lead on truck lanes. And maybe NJ with Portway will follow on the east coast. And Seattle could be next. And I-80 across PA concessioned out as a truck turnpike?

The NJ Turnpike with a dual/dual arrangement and trucks confined to the central pair of roadways for a substantial length into the ports of Elizabeth, if it got together with PA and IL turnpikes and CA or WA could perhaps stitch together a coast to coast triples, turnpike doubles or B-trains roadway. There could be huge new business at the staging points at interchanges. Hopefully in Maine they will be working with their neighbors to think of mutual benefits running heavy road trains on the proposed east-west turnpike.

This TS&W study, for all its silly shilling for the railroads, at least reveals the huge user benefits of road trains and their positive environmental potential. But this clumsy USDOT bureaucracy is only randomly and unreliably a force for positive change, which mostly has to come from local initiatives like those of SCAG in Los Angeles, the OH turnpike, and hopefully guys at innovative pavement designers like Koch, clever bridge builders like JM Muller and highway designers like Joel Marcuson of Sverdrup. Maybe one day, the truckers? Still the report’s well worth getting ahold of, and using selectively. Meanwhile they say they want comment on this report. (Contact USDOT 202 366 5580 www.fhwa.dot.gov)